I apologize if my previous reply came across as too curt. But I think a sharp distinction needs to be drawn between two work systems that are quite different:
A. Market based, in which a certain reward is provided for performing a certain amount of work. Workers are generally free to come and leave, and respond accordingly to variations in wages.
B. Command based, into which workers are essentially corralled by threats of force (explicit or implicit), and often provided with nourishment so they can keep laboring until their obligation is fulfilled.
It's possible to talk of "payment" under scenario B [1], but it cheapens the term and it definitely doesn't indicate market-based relations. Transfers of food and drink (which make for poor currency, especially in places that are already minting coins [2]) are on the contrary a good indication of the corvée system at work.
[1] See e.g. this Wikipedia entry: "Corvée [...] was unpaid labour imposed [...] by the state [...] The corvée was the earliest and most widespread form of taxation [... The] Medieval agricultural corvée was not entirely unpaid: by custom the workers could expect small payments, often in the form of food and drink consumed on the spot." http://en.wikipedia.org/wiki/Corvee
Although if I may digress and make a small comment. The market economy could be argued somewhat "command based" too. The difference being that you are given money to buy the food and shelter you need (rather than being given them directly). And then you have the entire "debt economy" when it comes to "laboring until their obligation is fulfilled".
While I now understand your argument, I saw the issue more as the state at least acknowledged an exchange, and a right for the worker to receive some compensation. Perhaps not the most valuable. But something, in a time were you could easily have slave labor; "payment" in its simplest form without any connotation to specific economic models.
Speaking of slave labor however. There was a part about slaves (in one of the articles I quoted). It stated that more skilled labor (doctors, nurses and teachers) were kept as slaves. Now, in a market economy those kinds of skills would (should) be especially rewarding in the model A you are talking about.
When I think about it, I can't say that lower skill work really would seem to differ in the two models you mentioned. In today’s world you could find lower skill work that pays more than simply keeping a person alive (e.g. in many European countries), but generally speaking this is not true in all (most?) places.
A. Market based, in which a certain reward is provided for performing a certain amount of work. Workers are generally free to come and leave, and respond accordingly to variations in wages.
B. Command based, into which workers are essentially corralled by threats of force (explicit or implicit), and often provided with nourishment so they can keep laboring until their obligation is fulfilled.
It's possible to talk of "payment" under scenario B [1], but it cheapens the term and it definitely doesn't indicate market-based relations. Transfers of food and drink (which make for poor currency, especially in places that are already minting coins [2]) are on the contrary a good indication of the corvée system at work.
[1] See e.g. this Wikipedia entry: "Corvée [...] was unpaid labour imposed [...] by the state [...] The corvée was the earliest and most widespread form of taxation [... The] Medieval agricultural corvée was not entirely unpaid: by custom the workers could expect small payments, often in the form of food and drink consumed on the spot." http://en.wikipedia.org/wiki/Corvee
[2] http://en.wikipedia.org/wiki/Persian_daric